For some time now, beta blockers have been suspected of increasing the risk of Parkinson’s disease. According to a recent review, however, a causal relationship is very unlikely. The experts therefore advise against stopping the medication prematurely.
Beta-receptor antagonists (in short: beta blockers) such as atenolol, bisoprolol, propanolo or metoprolol are often used to lower high blood pressure. They can also be prescribed for heart failure and coronary heart disease. However, some studies have found evidence that there may be a link between long-term beta blockers and the onset of Parkinson’s. Many patients, but also doctors, were unsettled as to whether they should better stop using beta blockers.
A current review, which was published in the specialist magazine “Lancet”, has now summarized the current state of knowledge, as reported by the German Society for Neurology (DGN). Accordingly, patients should not stop taking their medication for fear of Parkinson’s disease. The benefit of beta blockers, for example after a heart attack, is much higher than the possible risk of Parkinson’s, the authors said.
Relationship between beta blockers and Parkinson’s risk not established
The study, which suggested an increase in Parkinson’s risk from long-term therapy with beta-blockers, is an epidemiological observational study. However, a basic investigation has also found a mechanism in cell experiments that has not yet been confirmed, according to which the beta-blocker propranolol up-regulates the production of α-synuclein, the main component of the Lewy bodies. It is known from genetic studies that an increased presence of α-synuclein leads to a more frequent occurrence of Parkinson’s. A causal relationship between the use of beta-blockers and the risk of Parkinson’s is far from proven.
“The associations between beta blockers and increased Parkinson’s risk could also be the result of statistical distortions and confounding factors,” emphasizes PD Dr. Franziska Hopfner, first author of the study. She also points out that observational studies cannot prove cause-and-effect relationships.
Early Parkinson’s symptoms presumably treated with propranolol
In her work, she analyzed the relationships more closely: “Our investigation was able to show that the increased risk of Parkinson’s disease among beta-blockers could no longer be demonstrated if patients with tremor were excluded,” said Hopfner. Since unspecific tremor is one of the very early, if uncharacteristic, signs of Parkinson’s (so-called Prodromi), propranolol was probably used to treat the prodromal Parkinson’s symptom tremor, but is therefore not the cause of the disease. This would also explain why Primidon, which is also used for tremor treatment, also appeared to be associated with an increased risk of Parkinson’s – an effect that also disappears when these patients are excluded from the statistics.
Results may be skewed by other factors
The association between beta-receptor agonists (salbutamol) and a protective effect against Parkinson’s found in a previous study has not yet been confirmed. Other factors could also play a role here, according to the authors of the current work, e.g. B. patients’ nicotine consumption. Various observational studies have shown that smokers are less likely to develop Parkinson’s than non-smokers. Heavy smokers in particular, however, belong in principle to the group of patients with chronic lung disease who are regularly prescribed beta-receptor agonists, so that the supposedly protective effect of beta-agonists in these patients could also be explained by nicotine consumption.
“Of course, nicotine is not recommended as a Parkinson’s prophylaxis. The risk of becoming ill and dying from the known consequences of smoking is significantly higher than getting Parkinson’s disease at all, ”says Hopfner. “Conversely, of course, there is no point in avoiding beta blockers to reduce the risk of Parkinson’s disease and, for example, risking a heart attack or not treating high blood pressure.”
Using beta blockers is higher than risk
“Even if there was a causal connection between beta blockers and Parkinson’s disease, which is not currently proven, it can be classified as low according to the current state of knowledge,” emphasizes Hopfner. According to the Lancet Neurology report, only one Parkinson’s disease would be arithmetically caused in 10,000 patients after five years of propranolol treatment. Doctors and patients should not panic and prematurely stop beta-blockers, the authors say. This would do more harm than good to health.
Photo: © Rob Byron – stock.adobe.com
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